1. Field of the Invention
The present invention relates to an optical lens system for taking image, and more particularly to a miniaturized optical lens system for taking image used in a mobile phone camera.
2. Description of the Prior Art
In recent years, with the popularity of the mobile phone camera, the optical lens system for taking image has become thinner and thinner, and the electronic imaging sensor of a general digital camera is typically a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) sensor. Due to advances in semiconductor manufacturing, the pixel size of sensors has been reduced from the early 7.4 um to the current 1.4 um. Therefore, there's increasing demand for miniaturization of the lens system.
To correct aberrations, a conventional mobile phone's lens assembly usually consists of three lens elements, one of the typical structures is the positive-negative-positive Triplet type. However, when the length of the lens assembly is reduced from 5 mm to less than 3 mm, less space is available for the optical system, making it difficult to incorporate three lens elements into the space of the optical system. Furthermore, the lens elements must become thinner, causing poor uniformity if the lens is made from plastic injection molding.
The present invention mitigates and/or obviates the afore-mentioned disadvantages.